The invention relates to a bearing device which can be suitably used in an environment in which the temperature largely changes.
Conventionally, a bearing device is used in which a shaft having dynamic pressure grooves is fitted into a sleeve made of a copper alloy.
In such a bearing device of the prior art, the sleeve and the shaft are made of materials of different kinds and have different coefficients of thermal expansion. Therefore, such a bearing device has a problem in that, when the temperature is changed, the gap between the sleeve and the shaft is largely changed and the supporting performance due to a dynamic pressure is lowered.